The add on furnace is designed to use in conjunction with your existing HVAC ductwork and work seamlessly with your existing furnace. With twin 550 CFM blowers and up to 139,000btus it is designed to heat a home up to 2500 sq. ft. This unit is made with a firebrick lined plate steel firebox surrounded by brilliant red painted steel giving the unit an eye appealing look. Connection to your existing ductwork is easy with the two heat outlets. Available accessories include the Universal filter box Kit.